Polarization mode dispersion, referred to as PMD, adversely affects high-speed optical data transmission. A method for measurement of polarization mode dispersion has been described in the Conference Proceedings of the European Conference on Optical Communication, Amsterdam, NL, Sep. 30–Oct. 4, 2001, Tu.A.3.4, in which a polarization scrambler is used which can produce a large number of output polarizations, or all possible output polarizations, from a specific input polarization. The output polarizations which can be produced define a three-dimensional, not just two-dimensional, figure within the Poincaré sphere. Further polarization scramblers are described in Electronics Letters, Volume 30 (1994)18, pages 1500–1501. These can produce a depolarized output signal from any given input polarization. At least for certain input polarizations, the output polarizations which are produced define, however, only a two-dimensional, and not a three-dimensional, figure within the Poincaré sphere since depolarization is a necessary but not necessarily sufficient precondition for output polarizations actually being produced which define a three-dimensional figure, and not just a two-dimensional figure, within the Poincaré sphere.
Ideally, the output polarizations which are produced should be uncorrelated; that is to say, the correlation matrix of the normalized Stokes vectors of the output polarization should be equal to ⅓ times the 3×3 unit matrix.
The polarization scrambler should be designed to be as simple as possible and to scramble the polarization within a time which is as small a multiple as possible of the cycle duration of the highest frequency oscillation which is required to drive the polarization scrambler.
An object of the present invention is to specify a polarization scrambler which is as simple as possible but is still ideal, as well as an associated method for polarization scrambling, which emits uncorrelated output polarizations.